The invention concerns a process for the staining of polyvinylbutyrate in sheet form which later is used as a welding compound in the manufacture of laminated and bulletproof glass panes.
Until now, the polyvinylbutyrate has been manufactured and sold in the form of rolls in a transparent, stained or only in one uniform transparent color, with a gradating stripe of uniform shading of coloring, which was used, for example, for automobile windshields. There was also an opaque, white type.
In order to obtain all these variants, the polyvinylbutyrate was stained before it took its lamellar shape, in which case a pigment or stain was added to the paste, which, if necessary, could be added only at one end of the sheet resulting in the formation of a blurring stripe.
Until then, it had not been possible to obtain any kind of coloring after completed manufacture of the sheet in polyvinylbutyrate. Especially, it had never been possible to produce any type of pictorial representation or differentiated coloring on the basis of one or several colors, particularly a coloring with a marble or an alabaster effect, especially because the polyvinylbutyrate could not absorb any color without losing its basic characteristics which consist of welding the glass panes together.
The object of the invention is to obtain at least one staining, that is as differentiated as possible, on polyvinylbutyrate in sheet form, with one or several shades and according to drawings showing marble, alabaster etc.; i.e., to obtain a staining that represents imaginative drawings.